Hundreds of American soldiers exposed to chemical weapons during the occupation of Iraq didn’t receive proper care, the Department of Defense now admits. In fact, many were sent on their way with no treatment and told not to talk about the injuries they sustained from the exposure.

The controversy first surfaced when The New York Times reported that U.S. forces found old, leaking stockpiles of chemical weapons from the 1980s. The munitions included mustard gas and sarin, which injure on contact.

The Times reported that one soldier, Jordan Zoeller, was exposed to a sulfur mustard agent when destroying chemical artillery shells in 2008. He was told his breathing and skin problems did not come as a result of his exposure. “No one ever believed me,” he said. “They were like, ‘Oh, that never happened.’”

The number of soldiers suffering from the exposure was first pegged at 17, then 25 by the Times. But now the Pentagon says its own internal review shows at least 629 service personnel have reported complications from being exposed to the weapons and there could be others who were affected as well.

“The new and larger tally of potential cases suggests that there were more encounters with chemical weapons than the United States had acknowledged and that other people—including foreign soldiers, private contractors and Iraqi troops and civilians—may also have been at risk,” the Times’ C.J. Chivers wrote.

Military units cited by the newspaper whose members were exposed were three Army explosive ordnance disposal companies and B Company, First Battalion, 14th Infantry.

The Pentagon now says it will expand its outreach to service members who might have been wounded when dealing with chemical weapons in Iraq and has established a phone number, 1-800-497-6261, for veterans to report possible exposure.